examples/api: improve determination of LOAD_ADDR

The current load address for the 'demo' binary does not work for
qemu_arm_defconfig.

The suitability of an address to load an ELF binary and run it does
not only depend on the architecture but also on the memory layout of
the board.

On most boards we can assume that 8 MiB of memory is available above
$loadaddr. So $loadaddr + 0x400000 should work there.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/examples/api/Makefile b/examples/api/Makefile
index 722c7e4..be97b80 100644
--- a/examples/api/Makefile
+++ b/examples/api/Makefile
@@ -5,26 +5,9 @@
 # Provide symbol API_BUILD to signal that the API example is being built.
 KBUILD_CPPFLAGS += -DAPI_BUILD
 
-ifeq ($(ARCH),powerpc)
-LOAD_ADDR = 0x40000
-endif
-ifeq ($(ARCH),arm)
-ifdef CONFIG_64BIT
-LOAD_ADDR = 0x40400000
-else
-LOAD_ADDR = 0x1000000
-endif
-endif
-ifeq ($(ARCH),mips)
-ifdef CONFIG_64BIT
-LOAD_ADDR = 0xffffffff80200000
-else
-LOAD_ADDR = 0x80200000
-endif
-endif
-ifeq ($(ARCH),riscv)
-LOAD_ADDR = 0x84000000
-endif
+# Environment variable loadaddr is set from CONFIG_SYS_LOAD_ADDR.
+# Run the examples 4 MiB above this address.
+LOAD_ADDR:=${shell printf 0x%X $$(( $(CONFIG_SYS_LOAD_ADDR) + 0x400000 ))}
 
 # Resulting ELF and binary exectuables will be named demo and demo.bin
 extra-y = demo